Ullu means an owl, but it is also used for a stupid person.
Oh ,Really? Do you think me to be so much ullu as to believe in him?
see ulu

means "Owl" ... used an as insult in south asia. especially with puttha
Ullu ka puttha -- son of an owl
by abarjiga March 7, 2007
ullu ka patha/ patta/ phatta meaning Son of an owl literally but used to call someone a fool
He is an ullu ka patha.
That ullu ka patha is my brother.
by Urban Indian September 18, 2013
Also interpreted as 'a friend of' . Ullo means owl literally and anyone so addressed is implied to be foolish. Thus a friend of one is also implied to be as foolish if not more :)
Essentially a Hindi/Urdu phrase common in northern India:
tum hara kya kehna , tum to ullu ka patha ho!
by pyaasi churail March 6, 2016